New lubricating oil additives

ABSTRACT

New lubricating oil additives are provided comprising the reaction product of diphenylolpropane with an aliphatic chain substituted-succinic anhydride or acid, which aliphatic chain substituent is substantially saturated and contains at least about 30 carbon atoms, said reaction product being neutralized with an amine, preferably a polyamine, such as a polyalkylenepolyamine. Lubricating oils, fuel oils, and carburants containing the new additives have excellent detergent, dispersing and anti-rust properties.

United States Patent 1 1 Demoures et al.

1 1 Jan. 28, 1975 NEW LUBRICATING ()IL ADDITIVES [75] Inventors: BernardDemoures, Puteaux', Daniel Llauro, Crepieux Le Papc; Francois Giolito,Lyon, all of France [30] Foreign Application Priority Data July 8. 1971France 71/26025 [52] LBS. Cl. 260/479 S, 44/71, 252/51.5 A [51] Int. ClC07c 69/00, COlm 3/26 [58] Field of Search 260/479 R, 479 S; 252/515 A[56] References Cited UNITED STATES PATENTS 3.278.550 10/1966 Norman etal 252/515 A Le Suer 252/515 A Honnen et al. 252/515 A 7/1970 ll/l97lPrimary I:'.ruminw-Paul F. Shaver [57] ABSTRACT New lubricating oiladditives are provided comprising the reaction product ofdiphenylolpropane with an aliphatic chain substituted-succinic anhydrideor acid. which aliphatic chain substituent is substantially saturatedand contains at least about 30 carbon atoms. said reaction product beingneutralized with an amine, preferably a polyamine, such as apolyalkylenepolyamine. Lubricating oils, fuel oils, and carburantscontaining the new additives have excellent detergent, dispersing andanti-rust properties.

8 Claims, N0 Drawings 1 NEW LUBRICATING OIL ADDITIVES BACKGROUND OF THEINVENTION The present invention relates to new lubricating oil additiveswhich impart to lubricating oils good detergent, dispersing andanti-rust properties. This invention relates also to lubricating oilsand to fuels and carbura'nts containing said additives.

There are known to the prior art, additives for lubricating oils whichconsist of derivatives of succinic acid or anhydride substituted withslightly unsaturated hydrocarbons. This class of additives, which hasbeen known for some years, was an important development to thelubricating oil art. They consist mainly of reaction products ofsuccinic acylating agents, substituted with a fairly saturatedhydrocarbon radical containing an aliphatic chain of at least about 50carbon atoms, with amines or alcohols.

Though the performances of such prior art additives are acceptable, itis desirable and even necessary to improve them. Those additives of theprior art which are esters have deficiencies with regard to theirbehavior to high temperatures and to their lack of resistance tohydrolysis. The esters are good anti-rust agents, but they have alimited dispersing power. Those additives which are aminated derivativesare good ashless dispersing agents, but they possess poor anti-rustproperties.

It is an object of the present invention to provide a lubricating oiladditive which does not have the shortcomings of the prior artadditives.

It is also an object of the present invention to provide lubricatingoils containing the new additives and which oils have improveddispersing, detergent and anti-rust properties.

Another object of the present invention is the provision of alubricating oil additive having improved properties over those of theprior art alkyl substituted succinic esters described, for example, inU.S. Pat. No. 3,381,022 granted Apr. 30, 1968, and also with regard tothe amide derivatives described in U.S. Pat. No. 3,172,892 of Mar. 9,1965.

Other objects of the invention will be apparent to those skilled in theart from the present description.

GENERAL DESCRIPTION OF THE INVENTION The lubricating oil additives ofthe present invention comprise reaction products of diphenylolpropanewith an hydrocarbon chain substituted succinic anhydride or acid, whichhydrocarbon chain substituent is substantially saturated and contains atleast 30 and preferably at least 50, carbon atoms, said resultingproduct being then neutralized with a polyamine, such as apolyalkylenepolyamine. After an extensive research investigation it hasbeen found that these additives impart improved detergency, dispersingand anti-rust properties to lubricating oils, fuel oils and carburants.

These novel additives and products of the invention are produced in theform of a complex mixture, rather than a precise chemical compound, ofwhich it is difficult to determine the exact chemical composition andthe relative proportions present of the various constituents. It is forthis reason that the products must be described in terms of the processof manufacturing them. The presence of the ester grouping resulting fromthe reaction of the diphenylolpropane and the substituted succinicanhydride or acid has been confirmed by infrared analysis. Theesterification reaction between the substituted succinic acid oranhydride and diphenylolpropane results in an equilibrium difficult todisplace; the resulting product contains in solution a variableproportion of the unreacted succinic acylating agent and, as adispersion in said solution, unreacted diphenylolpropane. It isessential, in order to obtain good dispersing properties when employingthe product as a lubricating oil additive, to neutralize the unreactedacylating agent with an amino compound. The unreacted diphenylolpropanemay be removed, if it is in a large excess, by any convenient way suchas filtration, centrifugation, etc.

The hydrocarbon chain-substituted succinic acid or anhydride startingmaterials used in the present invention are those resulting from thereaction ofmaleic acid or anhydride with a polyolefin, such aspolyethylene, polypropylene, polybutylene, polyisobutylene, etc. havinga molecular weight sufficient to provide a carbon content of at leastabout 30 atoms, preferably at least about 50 carbon atoms. Thehydrocarbon chain is preferably aliphatic in nature. As a practicalmatter, the molecular weight of such polyolefins is at least about 400.It is also possible to use a chlorinated polyolefin, such aschloropolyethylene, which is reacted with maleic acid or anhydride. Allthat is necessary is to react the maleic anhydride with the polyolefinor chlorinated polyolefin at a temperature of between about 150 and250C. The reaction product is the polyolefin-substituted succinicanhydride. The substantially saturated hydrocarbon substituent of thesuccinic radical may contain polar groups in minor proportions: chloro,nitro, etc. Hydrolysis of this product by water or steam treatment willproduce the corresponding succinic acid.

The esterification reaction of diphenylolpropane with the aliphaticsubstituted succinic anhydride or acid may be achieved in the presenceof a classical esterification catalyst, i.e., a base or acid, such aspyridine or its hydrochloride, sulfuric acid, para-toluenesulfonic acidand ion exchange resins having a strongly or moderately acid character.It may also be achieved without any catalyst. This esterificationreaction occurs preferably at a temperature from about 50 to 300C,preferably between about and 200C, with or without a solvent such asxylene, toluene, etc. The solvent simplifies both temperature controland water removal from the reaction mixture.

The relative proportions of the two constituents, diphenylolpropane andaliphatic substituted succinic acid or anhydride, may vary within largelimits. But in any event, since esterification is usually not complete,the remaining acid or anhydride must afterwards be neutralized with anaminated compound. Such neutralization is an important feature of theinvention, as it is necessary to obtain good dispersing properties. Theunreacted diphenylolpropane, finely dispersed in the product resultingfrom the esterification reaction, may be removed if it is in asubstantial quantity. Otherwise it may remain in the product in adivided form without involving any disadvantage or incompatibility.

The esterification reaction involves a time duration of between about 1and 10 hours, preferably 2 to 6 hours. It may occur under the normalatmospheric pressure, or under an elevated or reduced pressure, or in anatmosphere of inert gas.

The unreacted substituted succinic acid or anhydride present in theproduct resulting from esterification is DETAILED DESCRIPTION OF THEINVENTION In order to disclose more clearly the nature of the presentinvention, the following examples illustrating the invention are given.It should be understood, however, that this is done solely by way ofexample and is intended neither to delineate the scope of the inventionnor limit the ambit of the appended claims. In the examples whichfollow, and through the specification, the quantities of material areexpressed in terms of parts by weight, unless otherwise specified. Theacylating agent used in Examples 1 to 6 hereinbelow is the reactionproduct of 350 grams of maleic anhydride and 2500 grams of polyisobutenewith a molecular weight equal to about 1000.

EXAMPLE 1 2 kilograms of polyisobutylene substituted-succinic anhydride,prepared as hereinabove [Pibsa index 53 Pibsa index (for polyisobutenylsuccinic anhydride) is the number of potash milligrams which arenecessary for neutralizing 1 gram of product] were reacted with 107grams of diphenylol propane in the presence of 21 grams ofp-toluenesulfonic acid catalyst for 4 hours at a temperature of 160C.The product was then vaporized under vacuum at 160C. for 1 hour, andneutralized with 82 grams of tetraethylenepentamine at 155C. for 2hours, under a partial vacuum (400 mm. Hg. pressure, approximately).This treatment was followed with a vaporization at mm. Hg. pressure for30 minutes. Nitrogen content in the final product was 1.29%.

EXAMPLE 2 62.5 grams of diphenylolpropane were heated at 170C. 484 gramsof polyisobutylene substitutedsuccinic acid prepared as hereinabove(Pibsa Index 63.5) were introduced over 15 minutes at 170C. under 400mm. Hg. pressure. The reaction proceeded for 4 hours (170C. underpartial vacuum). 543 grams of the resulting product were treatedafterwards with 21.5 grams of tetraethylenepentamine under the sameconditions as in Example 1. Nitrogen content in final product was 1.40%.

EXAMPLE 3 64 grams of diphenylolpropane were heated in the presence of472 grams of xylene at 1 l0-115C. Then 1257 grams of polyisobutylenesubstituted-succinic anhydride prepared as hereinabove, (Pibsa Index62.5 were introduced over a period of minutes. After 1 hour of reactionat 110115C., 13.2 grams ofpyridine were added. A second addition of anequal amount of pyridine was made after 2 hours of reaction. After 3.5hours of reaction, the product is vapourized at 140C. under 20 mm. Hg.pressure for minutes.

EXAMPLE 4 200 grams ofthe product of Example 3 were neutralized with 5.6grams of tetraethylene pentamine under the same conditions as inExample 1. Nitrogen content of the final product was 1%.

EXAMPLE 5 200 grams of the product of Example 3 were neutralized with7.7 grams of triethylenetetramine under the same conditions as inExample 1. Nitrogen content of the final product was 1.42%.

EXAMPLE 6 6640 grams of polyisobutylene substituted-succinic anhydride(Pibsa Index 76.3) were reacted with 465 grams of diphenylolpropane inthe presence of 53 grams of para-toluene sulfonic acid for 2.5 hours at162.5C. Then the product was vapourized under vacuum for 1.5 hours. 667g. of the resulting product were neutralized with 23.1 grams oftetraethylenepentamine under the same conditions as in Example 1.Nitrogen content of the final product obtained in this way was 1.23%.

EXAMPLE 7 The acylating agent employed in this example was the reactionproduct of maleic anhydride with a polyisobutene having a molecularweight equal to about 455, heated at a temperature between 190 and 240C.for 10 hours.

200 grams of the resulting polyisobutylene substituted-succinicanhydride (Pibsa Index 81) were reacted with 16.46 grams ofdiphenylolpropane and 2.1 grams of p-toluene-sulfonic acid over 4 hoursat 170C. and for 30 minutes under vacuum at 170C. 201 grams of theresulting product were reacted with 9 grams of tetraethylenepentamine atC. for 2 hours under partial vacuum (about 400 mm. Hg. pressure).Treatment was completed under vacuum of 20 mm. Hg. pressure for 30minutes. Nitrogen content of the final product was 1.44%.

It will be apparent that in the foregoing examples other polyolefinsubstituted succinic anhydrides may be employed such as those ofpolyethylene, polypropylene and polypentene, etc. Also, the amineemployed for neutralization may be diethylenetriamine orpentaethylenehexamine, etc.

The additive products of the invention, including the products of theforegoing examples, are desirably employed in lubricating oils, fueloils and carburants. in amounts of between about 0.01 and 10%,preferably between 0.1 and 3%, by weight of oil.

The foregoing products according to the present invention were testedwith regard to anti-rust and dispersing properties in lubricatingagents.

The tests of the dispersing power were conducted according to the stainmethod described in Volume 1 of A. Schillings book Les huiles pourmoteurs et le graissage des moteurs (Oils for motors and motorgreasing), edition of 1962, pages 89-90. Stains were achieved with theadditive dissolved in a lubricating oil of SAE 30. Sludge was added inorder to obtain a content of carbonaceous substances of 0.36%. There arefive stains obtained:

1. after heating at 200C. for 10 minutes 2. after heating at 250C. for10 minutes 3. after-heating at 200C. for minutes (at the outset 1% ofwater was added) 4. after heating at 200C. during 1 minute (initially 1%of water was added) 5. after adding of 1% of water, in the cold stateReadings were made after 48 hours. For every stain, the dispersed sludgepercentage is expressed with regard to the oil stain and calculated fromthe respective diameters. The higher the percentages of dispersedproduct; the better is the dispersion with regard to sludge.

For the products in accordance with the present invention of theforegoing examples the following values were obtained:

Example 1 product= 308 Example 2 product 306 Example 4 product 301Example 5 product 312 A comparison was made of the dispersing valuesobtained by the same test method with other products such as anon-neutralized ester and prior products commonly used,'considered astypical of the present state of the art. Listed below are the valuesobtained:

Product of Example 3'(non-neutralized product) 200 Monosuccinimide 268Bis succinimide 274 Ester of substituted succinic acid andpentaerythritol 265 Ester of substituted succinic acid and glycerol 250Ester of substituted succinic acid and phenol MONOSUCCINIMIDEPREPARATION 250' grams of polyisobutylene substituted-succinic anhydridehaving a Pibsa index 53 were reacted with 18 grams oftetraethylenepentamine at 155C. for 2 hours, under partial vacuum (about400 mm. Hg. pressure). Treatment was followed with a vapourization under20 mm. Hg. pressure for minutes. Nitrogen content of the final productwas 2.46%.

BIS-SUCCINIMIDE PREPARATION 250 grams of polyisobutylenesubstituted-succinic anhydride having a Pibsa index 55 were reacted with8.6 grams of triethylenetetramine at 155C. for 2 hours, under a partialvacuum (about 400 mm. Hg. pressure). Treatment was followed by avapourization under 20 mm. Hg. pressure for 30 minutes. Nitrogen contentof the final product was 1.32%.

PREPARATION OF SUBSTITUTED SUCCINIC ACID AND PENTAERYTHRITOL ESTER 1258grams of polyisobutylene substituted-succinic anhydride (Pibsa index62.5 were reacted with 94 grams of pentaerythritol for 3.5 hours at135-145C.

then for 2 hours at 175185C. Unreacted pentaerythritol was removed byfiltration. The filtrate constituted ester.

PREPARATION OF GLYCEROL AND SUBSTITUTED SUCCINIC ANHYDRIDE ESTER 898grams of polyisobutylene substituted-succinic anhydride with a PibsaIndex 62.5 were reacted with 46 grams of glycerol for 3 hours at C.,then for 3 hours at 190C. The reaction product was the desired ester.

PREPARATION OF PHENOL AND SUBSTITUTED SUCCINIC ACID ESTER 898 grams ofpolyisobutylene substituted-succinic anhydride with a Pibsa index 62.5were reacted with 376 grams of phenol in the presence of 190 grams ofxylene for 1 hour at -l65C. Afterwards 12.7 grams of p-toluene sulfonicacid were added. The reaction proceeded for 30 minutes at l60-l65C. Thisoperation was repeated twice. Finally, xylene, residual phenol andcatalyst were removed under vacuum (160165C. during 30 minutes 10 to 20mm. Hg. pressure). The final product was the ester.

The anti-rust characteristics of the products according to the inventionhave been tested in the laboratory with favorable results. The generaltendency has been confirmed by motor tests (sequence II B, gasolinemotor V-8 of a 1967 Oldsmobile). The basic formulation to which theadditive was added was composed of a calcium sulfonate, a calciumphenate and a zinc dithiophosphate. The following values expressingaverage engine rust (AER), were obtained (ideal value 10):

Basic formula plus Example 1 product AER 8.6

Basic formula plus Example 5 product AER 7.9

As a comparison of the prior art, the following value was obtained:

Basic formula plus bis succinimide AER 7.2

The entirety of the test results set forth hereinabove shows quite wellthe important improvement provided by the additives for lubricating oilsproduced according to the invention and characterizes the technicalprogress that such new products have achieved.

The terms and expressions which have been employed are used as terms ofdescription and not of limitation, and there is no intention in the useof such terms and expressions of excluding any equivalents of thefeatures shown and described or portions thereof, but it is recognizedthat various modifications are possible within the scope of theinvention claimed.

What is claimed is:

1. An additive consisting of the ester reaction product ofdiphenylolpropane with an hydrocarbon substituted-succinic anhydride oracid, wherein the said hydrocarbon substituent is substantiallysaturated and contains at least about 30 carbon atoms, said reactionproduct being neutralized with a polyamine.

2. An additive in accordance with claim 1, wherein said polyamine is apolyalkylenepolyamine.

3. An additive in accordance with claim 2, wherein saidpolyalkylenepolyamine is a member selected from the class consisting ofdiethylenetriamine, triethylenetetramine, tetraethylenepentamine andpentaethylenehexamine.

4. An additive in accordance with claim 1, wherein said hydrocarbonsubstituent is a polyolefin radical.

8 class consisting of polyethylene, polypropylene polybutylene.polyisobutylene. polypentene-l and chlorinated polyolefins.

8. An additive in accordance with claim 1. wherein the esterificationreaction is conducted at a temperature of between about 50 and 300C.

2. An additive in accordance with claim 1, wherein said polyamine is apolyalkylenepolyamine.
 3. An additive in accordance with claim 2,wherein said polyalkylenepolyamine is a member selected from the classconsisting of diethylenetriamine, triethylenetetramine,tetraethylenepentamine and pentaethylenehexamine.
 4. An additive inaccordance with claim 1, wherein said hydrocarbon substituent is apolyolefin radical.
 5. An additive in accordance with claim 1, whereinsaid hydrocarbon substituent is a chlorinated polyolefin radical.
 6. Anadditive in accordance with claim 1, wherein said hydrocarbonsubstituent contains at least about 50 carbon atoms.
 7. An additive inaccordance with claim 4, wherein said polyolefin radical is derived froma member of the class consisting of polyethylene, polypropylene,polybutylene, polyisobutylene, polypentene-1 and chlorinatedpolyolefins.
 8. An additive in accordance with claim 1, wherein theesterification reaction is conducted at a temperature of between about50* and 300*C.